Ancient artefacts from the Battle of the Teutoburg Forest examined at PETRA III
Looking someone in the eye: this turn of phrase takes on an entirely new meaning when small glass eyes unearthed during excavations on the fields of the Battle of the Teutoburg Forest are examined at PETRA III. The Kalkriese Museum and DESY are working together to study archaeological artefacts using X-rays.
The Battle of the Teutoburg Forest was a famous event in Roman antiquity. In AD 9, a Germanic army led by the legendary Arminius destroyed several Roman legions, halting the Roman advance into what was then Germania. Archaeological excavations at Kalkriese bear witness to this battle against Varus’s troops and have unearthed, among other things, bones, Roman militaria and coins as well as, most recently, an almost completely preserved set of the armour worn by legionaries. The remarkable items found on the battlefield also include six small glass eyes, each barely larger than a fingertip, some of them blue, others black.
These were recently examined at DESY using high-intensity X-rays from PETRA III to find out exactly what materials the Romans mixed into the glass during its manufacture to achieve the colours. These initial investigations recorded the X-ray, fluorescence and absorption spectra to find clues about the substances that lend the eyes their colour. These provided a clue to the actual pigments responsible for coloring. . Among the elements that could be responsible for the coloring and were found in the glasses in larger concentrations are iron, manganese, copper and lead. Black, for example, seems to have been produced by using a higher iron content. White glass is characterized mainly by its high lead content, suggesting the use of lead white (lead hydroxide carbonate); while the blue areas have higher copper contents. . The detection of various iron and iron/manganese containing pigments in black Roman glass can already be found as descriptions in scientific literature. A detailed analysis of the X-ray absorption spectra will determine which of these pigments were used in the glass eyes. The Kalkriese Museum plans to continue its cooperation with DESY at PETRA III: among other things, special X-ray methods are to be used to reveal the images once stamped on now completely corroded coins, and to analyse the corrosion processes inside an iron neck shackle.
Analytical methods that rely on synchrotron radiation sources, in particular micro-imaging methods, are ideally suited for studying cultural artefacts. These non-destructive methods provide more detailed insights into the molecular structure and the composition of materials, or how they are arranged. All this information furnishes archaeologists with information and insights into how and where individual artefacts were made. Investigating the processes that occur during corrosion, for example, also allows museums and curators to better preserve precious and unique cultural artefacts.
published
- 2022/10/27
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